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The Spintronics revolution may be just hope.



3D Hopfion

Artist’s drawing of the characteristic 3D spin surface of the magnetic hopfion. Berkeley Lab scientists have created and observed 3D jumps.This discovery could develop spintronics memory devices.Credits: Peter Fischer and Frances Hellman / Berkeley Lab.

A joint research study led by Berkeley Lab is critical to modern information technology.

A decade of discovery Quasiparticles, known as magnetic skyrmions, have provided an important new clue that microscopic rotation surfaces will enable spintronics to be a new class of electronic devices that use the direction of electron spin rather than charge to encode information.

But even though scientists have made big strides in this young field, But they still don̵

7;t understand how to design a spintronics material that will enable ultra-tiny, very fast and low-power devices. Skyrmions may seem promising. But scientists have long considered skyrmions to be two-dimensional objects. However, recent studies suggest that 2-D skyrmions may be the starting point for a 3D spin model known as hopfions, but no one has been able to prove that magnetic jumps are at the nanoscale.

Now, a team of researchers led by Berkeley Lab has reported. Nature communication The first demonstration and observation of 3D hopfions arising from nanoscale (billions of meters) skyrmions in a magnetic system. The researchers said their discovery heralds a step forward in the realization of low-power, high-density, high-density magnetic memory devices. But it is highly stable that takes advantage of the true power of the electron spin.

“Not only did we prove that there were complex spin surfaces like 3D hopfions, but we also demonstrated how to study and make use of them,” said Peter Fischer, senior co-author of the materials science department of the National Library of Medicine. Berkeley Lab, assistant professor in physics at UC Santa Cruz, “To understand how jumping really works, we need to know how to create and study it. The work is made possible because we have all these amazing tools at Berkeley Lab and our collaboration with scientists around the world, ”he said.

Based on previous studies, hopfions, unlike skyrmions, are that they don’t drift when moving along the device, so they’re a great option for information technology. In addition, theoretical collaborators in the UK speculated that the jumps could be caused by multilayered 2-D magnetic systems.

The current study is the first to put those theories to the test, Fischer said.

Using nanoscale tools to produce molecules at Berkeley Lab’s Molecular Foundry, Noah Kent, Ph.D., a physics student at UC Santa Cruz and in Fischer’s group at Berkeley Lab, worked with the Molecular Foundry staff to engrave nanopillars. Magnets from the layers of iridium, cobalt and platinum.

The multi-layer material was provided by UC Berkeley Postdoctoral Fellow Neal Reynolds under the direction of senior co-author Frances Hellman, Senior Lecturer in Berkeley Lab’s Department of Materials Science and Professor of Physics and Materials Science and Engineering at UC. Berkeley She also leads the project. Department of Energy’s Non-Equilibrium Magnetic Materials (NEMM), which supported this study.

The hopper and the sky are known to coexist in magnetic materials. But there is a spin pattern that is unique in three dimensions. The researchers used a combination of two advanced magnetic x-ray microscopy techniques – X-PEEM (X-Ray Radiation Electron Microscopy) at Berkeley Lab’s Synchrotron User Plant, an advanced light source. And a soft magnetic tomography (MTXM) microscope at ALBA, a synchrotron light manufacturing plant in Barcelona, ​​Spain, to create images of different spinning patterns of jumps and skies.

To confirm their observations, the researchers then performed detailed simulations to mimic how 2-D skyrmions within magnetic devices have evolved into 3D jumps in carefully designed multilayer structures and how they would appear when taken. Image with polarized X-ray light

“The simulation is a very important part of this process, allowing us to understand the experiments and design structures supporting sky jumps or other designed 3D spin structures,” said Helman.

To understand how the jumps ultimately work in the device, the researchers plan to use the unique capabilities of Berkeley Lab and world-class research facilities, which Fischer describes as “essential for the development of new technology. Such interdisciplinary work ”was to further study the dynamic behavior of quixotic quasiparticles.

“We have known for a long time that the spin surface is inevitably three-dimensional, even though it is a relatively thin film. But direct imaging is challenging to experiment, ”says Helman.“ The evidence here is exciting and opens the door to finding and exploring new and possibly even more significant 3D spin structures. ”

Reference: “Creating and Observing Hopfions in Multilayer Magnetic Systems” by Noah Kent, Neal Reynolds, David Raftrey, Ian TG Campbell, Selven Virasawmy, Scott Dhuey, Rajesh V.Chopdekar, Aurelio Hierro-Rodriguez, Andrea Sorrentino, Eva. Pereiro, Salvador Ferrer, Frances Hellman, Paul Sutcliffe and Peter Fischer, 10 March 2021, Nature communication.
DOI: 10.1038 / s41467-021-21846-5

Co-authors with Fischer and Hellman are David Raftrey, Ian TG Campbell, Selven Virasawmy, Scott Dhuey, and Rajesh V.Chopdekar of the Berkeley Lab; Aurelio Hierro-Rodriguez from the University of Oviedo and Andrea Sorrentino, Eva Pereiro, and Salvador Ferrer from the ALBA Synchrotron Country. Spain

Advanced Light Sources and Molecular Foundry are facilities for DOE Office of Science users at Berkeley Lab.

This event was sponsored by the US Department of Energy’s Office of Science




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